Both sugar and sugar alcohol are found naturally in food and are also added to processed items. Although they’re used similarly, they exhibit varying effects on your digestion, blood sugar levels, and oral health.

Sugar is the name of sweet-tasting carbohydrates that your body can convert into energy.

Sugar alcohols are also sweet-tasting. However, they have a different chemical structure, and your body does not absorb them as efficiently.

This article explains the important differences between sugar and sugar alcohol.

Sugars are sweet-tasting carbs. On a chemical level, they comprise carbon, hydrogen, and oxygen atoms.

They’re naturally found in foods like fruits, vegetables, grains, and dairy products, as well as added to processed foods.

Simple sugars can be divided into two main categories — monosaccharides and disaccharides.

Monosaccharides are the simplest type of sugar and contain just one type of sugar molecule.

Glucose is the simplest sugar and your body’s preferred source of energy. It’s the sugar that’s measured in blood sugar tests. Other monosaccharides are fructose and galactose, which are metabolized into glucose (1, 2).

Disaccharides are made up of two monosaccharide sugars bound together. They must be split apart for digestion (1, 2).

The most common disaccharide is sucrose, which is also known as table sugar and made up of a glucose and fructose molecule. Meanwhile, lactose is found in milk and made up of a glucose and galactose molecule, and maltose is made up of two glucose molecules.


Sugar refers to the sweet-tasting carbs that your body uses for energy. They’re made up of single or paired molecules known as monosaccharides (glucose, fructose, and galactose) and disaccharides (sucrose, lactose, and maltose), respectively.

Sugar alcohols, also called polyols, are a type of carbohydrate whose structure resembles both sugars and alcohol.

Still, sugar alcohols do not contain ethanol, and they’re thus safe for people who prefer to avoid alcohol.

Given that they’re similar to sugar, they can activate the sweet receptors on your tongue and have a pleasing, cooling effect on the taste of foods (1).

However, they’re not as efficiently absorbed or digested as regular sugar and therefore contain fewer calories.

They’re found naturally in some fruits and vegetables, such as plums, strawberries, and avocado, and also made by processing regular sugars.

Sugar alcohols are often used as lower calorie sweeteners in sugar-free chewing gum and candies, as food additives in processed foods, and in toothpaste, certain medications, and laxatives.

Common types of sugar alcohols include xylitol, erythritol, sorbitol, maltitol, mannitol, isomalt, and lactitol (1).


Sugar alcohols have a structure similar to that of sugars but also contain an alcohol molecule. This means they taste sweet but are not absorbed and metabolized in the same way as sugar.

Sugar and sugar alcohols differ significantly in sweetness, calorie content, and digestion, as well as their effect on blood sugar levels and oral health.

Calories and sweetness

Sugar alcohols contain fewer calories than regular sugars.

On average, they supply about 2 calories per gram, compared with the 4 calories per gram supplied by sugars (1, 3).

Additionally, they are often slightly less sweet, offering 25–100% of the sweetness of table sugar. Lactitol is the least sweet, and xylitol is just as sweet as sucrose (1, 3, 4).

Excessive sugar intake is linked to health conditions, such as obesity, heart disease, diabetes, and inflammatory diseases (2, 5).

Therefore, sugar alcohols may help reduce sugar intake by providing a lower calorie alternative to sugar that still delivers a sweet taste (1, 6).


Sugars are digested in the small intestine and transported into the bloodstream to be further metabolized or used for energy (3, 7).

Conversely, your body does not digest sugar alcohols efficiently.

One exception is erythritol, which is well absorbed but not metabolized. Instead, it’s excreted through your urine mostly intact (3, 8).

However, most sugar alcohols pass through to your large intestine, where they’re fermented by gut bacteria.

At higher intake levels, this can cause bloating, flatulence, stomach pain, and diarrhea, particularly in individuals with irritable bowel syndrome (IBS) (3, 9, 10).

Current recommendations advise that moderate doses of 10–15 grams per day are usually tolerated. However, sensitive people may need to avoid sugar alcohols, particularly sorbitol and maltitol, or reduce their intake to avoid symptoms (3, 9, 10).

Effect on blood sugar levels

When sugars are eaten, they’re broken down into a simple form and absorbed into the bloodstream, causing a rise in blood sugar levels (7).

Then, insulin transports the sugars into your body’s cells to either be converted into energy or stored (7).

The glycemic index (GI) measures how quickly a food raises your blood sugar levels. Glucose has a GI of 100, while sucrose has a GI of 60, meaning both have a high GI (11, 12).

Given that sugar alcohols are not efficiently absorbed, they have a much less significant effect on your blood sugar levels and thus a lower GI, with values ranging between 0–36 (1).

Therefore, sugar alcohols can be a good alternative for people with pre-diabetes, diabetes, or metabolic syndrome.

Tooth decay

Sugars are fermented by bacteria in your mouth, which can produce acids that damage your tooth enamel and increase your risk of dental caries (1).

Sugar alcohols do not contribute to tooth decay, as the bacteria in your mouth are unable to ferment them (1).

In fact, xylitol and erythritol may even help prevent tooth decay, which is why it’s often used in toothpaste and sugar-free mints or gums. However, more research is needed (13, 14, 15).


Sugar alcohols are generally less sweet than sucrose and have fewer calories. They’re also less digestible, which may cause side effects in some people. On the other hand, sugar affects blood sugar levels more and may contribute to tooth decay.

Sugar and sugar alcohols are sweet-tasting carbs with slightly different chemical structures.

Sugar alcohols are generally less sweet and contain fewer calories than sugars. They also affect blood sugar levels less significantly, making them a suitable alternative for people with diabetes.

Additionally, they’re not linked to tooth decay and may even help prevent it.

However, unlike sugar, they’re not well absorbed by the body. This means that when they’re consumed in large quantities or by sensitive individuals, they can cause bloating, flatulence, stomach pain, and diarrhea.